In the related art, technology for performing maintenance or management using an Ethernet (registered trademark) operations, administration and maintenance (OAM) frame in a packet transmission network is proposed (see Patent Document 1). In addition, in a wireless packet transmission network of a multi-hop connection, a wireless link state fluctuates according to weather fluctuation or the like between relay stations. In order to implement appropriate wireless packet transmission according to this fluctuation, adaptive multi-rate (AMR) has been proposed. In AMR, wireless packet transmission in which a communication rate and a resistance characteristic are balanced is implemented by adaptively changing a modulation/demodulation scheme according to a wireless link state.